The HRG Incendiary Rifle is one of the Firebug'stier 3 weapons. It is a modified version of Demolitionist's M16 M203 Assault Rifle designed to fire incendiary munition that sets ZEDs alight. Its alternative mode allows to shoot incendiary grenades that cover surface with the ground fire and residual flames upon explosion. All of HRG Incendiary Rifle's attacks cause ZEDs to suffer from afterburn effects.

This weapon does three types of the damage - ballistic bullet damage, direct hit that only affects initial target and AOE explosion of the grenade.
Bullets set ZEDs on fire. Explosion spawns 4 residual flames and (on non-direct hit with the ZED) also a ground fire.
Damage Type Group: AssaultRifle, Ballistic_Shell, Fire.

Upgrades

Upg1 (700): Base damage x1.2, Base weight + 1.
Upg2 (1500): Base damage x1.4, Base weight + 1.
The second upgrade comes with no weight increment. Upgrades affect bullet damage (and its DOT since it is a % of the base damage) and grenade impact damage. Upgrades, however, do not increase ground fire and residual flame damage and most importantly upgrades do not increase explosive damage of the underbarrel grenade.

Notes

Grenade explosion does not spawn a ground fire on a direct projectile impact with the ZEDs but does spawn it otherwise. Does spawn residual flames all the time.

Firebug gets damage bonuses for both - bullets and explosive damage, as well as to all forms of damage over time this weapon causes.

Being Firebug-only weapon HRG Incendiary Rifle provides no access to elite reload animations, however Firebug's passive reload bonus works well cutting reload time (of both - magazines and grenades) by up to 20% making reload speed 25% faster (reload time x 0.8).

Amount of the recoil depends on the player's stance and movement. Crouching and aiming down the sights gives the lowest possible amount of the recoil.

Minimum travel distance for projectile to explode = 3.87m.

Projectile travel speed = 40m/s.

Direct hit with the grenade does two types of the damage - ballistic (capable of damaging specific body parts, essentially it is a big slow bullet), then explosive (only does damage to body). Ballistic damage applied at all ranges, whether grenade exploded or not.

Projectile will collide with either - ZED's hitzone or a collision cylinder.